With reference to electrical charging systems for plug-in hybrid cars, electric cars or the like, in which rapid diffusion is hereinafter expected, SAE (Society of Automotive Engineers) of the USA and JEVA (current JARI: Japan Automobile Research Institute) had determined standard systems. In such standard systems, a plurality of modes have been established. For example, there is a mode (Mode 1) which requires only a charging cable and an earth leakage breaking means as a ground side facility, or a mode (Mode 3) which further requires, as a ground side facility, a control means including a charging control means which transmits a charging control signal (CPLT: Control Pilot) to a charging control circuit on the vehicle side. Contents of such standard systems are described in the portion of Background art of Patent document 1.
In the case of the vehicle adopting Mode 3 in the above mentioned modes, an electrical charging starts after the charging control circuit on the vehicle side checks a connecting status of a charging cable and a charging status of an in-vehicle battery.
FIG. 4 illustrates a schematic circuit diagram relating to a charging start control in a charging apparatus 20 for vehicles corresponding to a vehicle 30 adopting Mode 3. FIG. 5 illustrates a graph showing variation of potential of point A (a charging control signal) of the charging apparatus 20 for vehicles of FIG. 4 according to the charging status. In the schematic circuit diagram of FIG. 4, the potential of point A (a charging control signal) of the charging apparatus 20 for vehicles is set at 12 volt on the condition that a charging cable 1 is not connected with the vehicle 30 corresponding to Mode 3.
The charging cable 1 is configured with a power cable 1a which constitutes a charging electrical line, an information cable (communication cable) 1b which transmits a charging control signal, and an earth cable 1c. When the charging cable 1 is connected with the vehicle 30, a resistor R2 of a charging control circuit 6 on the vehicle side is connected with a resistor R1 in series, thereby reducing voltage, then the potential of point A (a charging control signal) becomes 9V. A charging control portion 7 can detect mutual connection between the charging cable 1 and the vehicle 30 corresponding to Mode 3. After that, the charging control portion 7 makes an oscillator 10 oscillate so that it becomes 9V oscillating status. Accordingly the 9 V pulse enters into the vehicle side and the charging start control circuit 6 on the vehicle side makes a receipt allowing switch 12 turned on. Consequently the potential of point A (a charging control signal) changes to 6V oscillation by reduction of voltage due to resistance of a resistor R3, so that preparation for receiving electrical power completes. On this condition, the charging control portion 7 outputs an ON signal to a relay 5, then charging electrical current flows through the charging electrical line 2, so that electrical charging to an in-vehicle battery 4 starts via a battery charger on the vehicle side.
The charging start control as mentioned above is performed by using an auxiliary battery used for other than driving on the vehicle side. However, there is a type of vehicles having a sleep mode function to stop power supply to the charging control circuit 6 for preventing the auxiliary battery of the vehicle 30 from running out if electrical charging does not start within a predetermined period of time after detecting mutual connection between the charging cable 1 and the vehicle 30. In case of restarting electrical charging to the vehicle from the sleeping mode, an operator needs to physically disconnect and reconnect the charging cable 1 in order to release the sleeping mode.
Relating to the charging apparatus 20 for vehicles, it is planned to have a timer control function for starting electrical charging after passing a predetermined period of time from the connection of the charging cable 1 in order to charge the vehicle 30 by using midnight power service with lower electrical utility rates, or to have a function to repeat start and stop of charging alternately in order to charge a plurality of vehicles by turns in multiple dwelling houses or the like. There was, however, a problem that such functions cannot substantially be utilized because the problems similar to the above occurs when the vehicle 30 having the sleeping mode function is connected with the charging apparatus 20 for vehicles.
Patent document 1: Japanese Unexamined Patent Publication No. 2009-71899 (Column of Background art)